Recently some field rock test methods of element testing were developed to investigate the mechanical properties of rock masses necessary for designs of various rock structures. These field test methods are in-situ triaxial compression test, in-situ uniaxial extension test and down-hole triaxial compression test.

In Japan, a standardization review committee was established in FY2017 in the standard section of the Japanese Geotechnical Society (JGS). After a one-year review, this review committee concluded that standardization was appropriate for two tests, the in-situ triaxial compression test and the in-situ uniaxial extension test. Then, a standardization committee was established in FY 2018, and the draft standards were circulated for public comment until June 2019. These standards will be published by March 2020.

Method for in-situ triaxial compression test on rocks

Method for in-situ direct tension test on rocks

In the paper presented, the brief overview of these new draft standards will be introduced. Then, focus is placed on their typical features that a wide variety of methods and/or techniques can be used for testing. This diversity related to the shape and size of the specimens, the structure of the test equipment, the control of loading, the instrumentation, etc., is contrary to the standardization that aims at the unification of the method. The reason for allowing such diversity is because it is preferable to conduct these tests under conditions that take into consideration the circumstances of the relevant site, since these tests are generally large-scale and have characteristics as boundary value problems.

1. Introduction

Recently some field rock test methods of element testing were developed to investigate the mechanical properties of rock masses necessary for designs of various rock structures. These field test methods are in-situ uniaxial/triaxial compression/extension tests which are similar to the corresponding laboratory tests. In 2017, Japanese Geotechnical Society set a working group to investigate the necessity of standardization for these test methods. After one year of discussion, this working group concluded that two tests methods, i.e. in-situ triaxial compression test and in-situ uniaxial tension test, should be standardized (JGS, 2018). The contents of the study by this review committee are introduced in Chapter 2.

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2019. Japanese Society for Rock Mechanics. Permission to distribute - International Society for Rock Mechanics and Rock Engineering
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